Substation telephone circuits



1927. June 21 ,w A J. RAY

sussunou Tswrnous cmcux'rs Filed June 22, 1922 Im.r5n n2:

fifihur J. Hair Z, %Zm% m Patented June 21, 1927.

UNITED #EEEIIEJ- Ben or Gam s ame OFFICE.

es -Isms B Maser. Ass eN r rrs; r

1 were-cc armors; QQMQBATION or were ete e -sense meme" 1 Application-filed June 22, 1922. Serial No. 570,229.-

The present invention relates to substaphone having the usual three spring switch hook combination for closing the talking circuits can be changedintoan automatic telephone by the addition of a calling device having the usual three s pi'ing shunt spring combination without adding switch hook springs. v I I t c A manual telephone changed as above mentioned has the characteristic that a subscriber who has such a'telephone may op crate the switches at the exchange by turning his calling device even though the I'-B7 ceiver is on thehook. This is due'to the fact thatthe shunt springsof the calling device, upon closing when the calling device is moved" irom' itsuiormal position,"close' a direct current bridge across the two line conductors in series with the bell. Then, as the calling device returns to its normal'po sition, the bridge across the line conductors is interrupted a number of times; In prior circuits of this general type, the tapping of the bell is depended upon to warn the subscriber that he is doing something that he should not do However, when a' harmonic bell, adjuste'd'to respond only to -a particular frequency of ringing current, is used, no tapping-occurs whenthe calling device isturned on account or the fact that the interruptions do not recur at the frequency forwhich the bell is adjusted. Consequent- 1y, asubscr-iber, knowing that the receiver must be removed before a call can bemade, may unthinkingly cause needless operation of the exchange switches by turning the calls i-ng device with the receiver on the hook, without at all suspecting that'theswitche's are responding. Accordingly, -it an ob ject of the invention to provide means independent ofthe bell fori'apprising the subscriber that he is doing something he: should not do when he turns the calling device while the receiver is the hook. I -This ob jectis accomplished by suitably changing thesubstation'. circuit so that current flows through the receiver in series with thej'bell 'wheiiwhe calling device is movedfrom' its normalpositionwhile the receiver is on the h'o'ol: and loud clicks-Hare heard in the receiver; The. improved circuit willr-now be explained with reference to the accompanying-drawing.

- Vith the receiver R on the: hook, the bell B is bridged across the line conductors 2 and in series with switch hook contacts 9 and the condenser C. When the receiver is removed, the bell B is disconnected at contacts -9 and a direct current bridge is. closed: across the'line. conductorsv 2 and 3 including the-upper winding of the induction coil-I, right hand switch hook contact, the switch hook, transmitter'T, and impulse springs rand 5 of the calling deviceCD.

Also the-receiverR, iniseries with the condenser and thelower winding of-the ill? duction coil I, is bridged around thetransmitter hen the calling subscriber turns the calling device GD'from its normal position, shunt springs 6,7, and 8 make contact with each other. Springs 7 and 8 shunt the trans: mitter T so as to-aiford abetter dialing-circuitfor the automatic, switches, and springs 6 and-'7; shunt the: lower winding of the i induction coil I so as to prevent the current induced in this winding from causing'fdis= agreeable clicks in thereceiver. As-the calliing device CD returns to, normal position, the bridge across the lineifconductors is opened the desired number of times at inrpulsesprings hand-5." I a 1 Assuming now that the receiver is on the switch hook and that the subscriber turns the calling device GD, a circuit is closed from line conductor 2 by wayv of the bell 13, contacts 9,: receiver R, shunt spring g'spfi,v

3?,and .8, and calling device springs 4 and I 5zto line conductor 3. As the calling device 'returnsto normal, springs 4 and 5 intere ruptsthe' bridge' across conductors 2 and 3 in the usualamanner. These interruptions, not onlyoperate the automatic switches in the exchange, but also-cause a corresponding causing. unnecessary operation, of the auto: matic switches. When the calling devlce reaches normaliposition, shunt springs 6', 7,

switchesfrelease in the usdslmannen v *Wha't claime d'isrf V .1. In a substation telephonejcircuit'," a

transmitter, a 1 receiver, threefswitch hook .nninberfofioud clicks infit-hereceiver R. These-clicks inform the subscriber that he is contacts adapted to close together when said receiver is lifted, two line conductors ter minating, respectively, in two of said switch hook contacts, an induction coil having two windings, a calling device having a pair of control contacts and three shunt contacts, said calling device having a normal position, said shunt springs adapted to make contact with each other when said calling device is turned from its normal position, one winding of said induction coil connected in series with one line conductor, said control contacts and said transmitter connected in series in the other line conductor, a bell and a condenser connected in series, the tree terminal of said condenser connected to one of said line conductors, the free terminal of said bell so connected as to afford a direct current path to the exchange from the last named free terminal, a third conductor cons nected at one end to the. junction of said bell and condenser and at the other end to the third of said switch hook contacts, the other winding of said induction coil and said receiver connected in series in said third conductor in the order named counting from the switch hook contactend of said 'third conductor, and circuit connections such that said other winding and said transmitter are shunted by said shunt contacts when said calling device is turned from its normal position.

2. In a substation telephone circuit, a transmitter, a receiver, three switch hook contacts adapted to close together when said receiver is lifted, two line conductors terminating, respectively, in two of said switch hook contacts, a calling device having'a pair of control contacts and three shunt contacts, said calling device having a normal posi tion, said shunt contacts adapted to make contact with each other when said calling device is turned from its normal position, an iduction coil-having one winding connected in series with one line conductor, said control contacts and said transmitter connected in series in the other line conductor, a bell and a condenser connected in series across said conductors, a connection from one terminal of said receiver to the junction of said bell and condenser, a connection including the other winding of said induction coil and extending from the other terminal of saidreceiver to the third of said switch hook contacts, and circuit connections such that said other winding and said transmitter are shunted when said shunt contacts close together.

3. In a substation telephone for automatic telephone systems, speech transmitting and receiving means including a transmitter and a receiver, a calling device for controlling the exchange switches, switch hook contacts for closing the talking and switch control circuits, calling device contacts for bridging nee-ease the receiver across the line independent of said hook contacts and circuit connections controlled by said hook contacts for shunting the receiver when the same is removed from the hook, whereby the receiver is caused to respond to impulses only in case the calling device is operated while the said receiver is on the hook.

4:. In a substation telephone for automatic telephone systems, a receiver for responding to incoming voice currents, a switch hook, a calling device, contacts controlled by said calling device for bridging said receiver across the line, and contacts controlled by said switch hook for shunting said receiver, whereby said calling device is adapted to control the exchange switches when the receiver is off said hook without affecting said receiver, while it the calling device is operated when the receiver is on the hook anoise is produced in said receiver to warn the subscriber.

5. In a substation telephone circuit,-an in,- duction coil, a transmitter, a receiver, a calling device having a pair of impulse springs, a bridge across the two line con ductors including in the order named the primary winding of said coil, the said transmitter and the said impulse springs, a connection from one side of the secondary wind-- ing of said coil to the junction of said primary winding and transmitter, a connection from the other side of said secondary winding to the junction of the transmitter and said impulse springs, said second connection including said receiver and a condenser, three shunt springs closed together responsive to the .actuationof said calling device, and shunt circuits closed by said shunt springs for removing the transmitter resistance from the bridge and for preventing noises in said receiver during the operation of said device.- 6. In a substation telephone circuit, an induction coil, a transmitter, a receiver, a calling device having a pair of impulse springs, a bridge across the two line conductors including in the order named the primary winding of said coil, the said transmitter and the said impulse springs, a connection from one side of the secondary winding of said coil to the junction of said primary winding and transmitter, a connection from the other side of said secondary wind ing to the junction of the transmitter and said impulse springs, said second connection including said receiver and a condenser and three contact springs closed together by'the actuation of said calling'device for shunting said receiver and said transmitter.

7. In a substation telephone for automatic telephone systems, a voice current receiver, a calling'device, contacts on said device for sending current impulses over the line when said receiver is on the hook and also'while it is oil the hook, and shunt springs controlled by said calling device for rendering said receiver unresponsive to said impulses only when said receiver is off the hook.

8. In a substation telephone for automatic telephone systems, a voice'current receivera calling device, contacts controlled by said device for sending current impulses over the associated line in series with said receiver, shunt contacts for rendering said receiver unresponsive to said impulses, and contacts operated upon the placing of said receiver on its hook for rendering said shunt contacts ineffective.

9. In a substation telephone circuit, a transmitter, a- Condenser and a receiver, a hook switch comprisingcontacts arranged to close and contacts arranged to open when said receiver is lifted, two line conductors terminating respectively in two of said hook switch contacts, a calling device comprising normally open shunt contacts and normally closed interrupter contacts, the latter in series with one of said line conductors, an induction coil having two windings one of which is in series with the-other of said line conductors, a receivenbridgeincluding said condenser, receiver and second winding of said induction coil, that bridge being.

'is moved oft-normal before the hook switch is operated.

10. In a telephone substatlon, a transmitter, a rece ver, a condenser, a ringer and an induction coil, a line: circuit containing said transmitter and one winding of said induction coil in series, there being normally a circuit bridged across said line including said condenser and said ringer but excludin'g said induction coil, and means comprising hook switch springs foropening the circuit of said ringer and for closing a shunt circuit-for said transmitter, said shunt circuit comprising said condenser, receiver and the second winding'ot said induction .coil, said condenser preventing the flow of direct current through said receiver.

In witness whereof, I hereunto subscribe my name this 19th day of June, A. D., 1922.

ARTHUR J. RAY. 

